add some comments to VirtualAsciiFile

}

VirtualAsciiFile::~VirtualAsciiFile() {

  // is it necessary to pop them out one by one? isn't there the dedicated method of std::vector to clean the vector?

  // besides, shouldn't this be done anyway by the destructor of std:vector?

  while (!_file_lines->size() > 0) {

    _file_lines->pop_back();

  }

}

void VirtualAsciiFile::append(const VirtualAsciiFile& rhs) {

  // concatenate the virtualasciifile pointed by rhs to the current one

  // can't we use the dedicated method insert of std::vector to do the appending, instead of an explicit loop?

  for (vector<string>::iterator it = rhs._file_lines->begin(); it != rhs._file_lines->end(); ++it) {

    _file_lines->push_back(*it);

  }

}

void VirtualAsciiFile::append_line(const string& line) {

  // append a line of output to the virtualasciifile

  _file_lines->push_back(line);

}

int VirtualAsciiFile::append_to_disk(const std::string& file_name) {

  // dump to disk the contents of the virtualasciifile, appending at the end of the given file_name

  int result = 0;

  fstream output_file;

  output_file.open(file_name, ios::app);

  int32_t final_index = position + end - start;

  if (final_index <= number_of_lines()) {

    for (int32_t li = start; li < end; li++) {

      // since here we are replacing the previous placeholder empty strings, make sure they are properly released when they are replaced (i.e. try it with a simple hello world example and pass it through valgrind)

      _file_lines->at(position++) = rhs._file_lines->at(li);

    }

  } else {

}

int VirtualAsciiFile::write_to_disk(const std::string& file_name) {

  // dump to disk the contents of the virtualasciifile, replacing the given file_name

  int result = 0;

  fstream output_file;

  output_file.open(file_name, ios::out);